Radiographic apparatus



June 23, 1959 R. 1 GUENTNER |:r AL 2,892,089

RADIOGRAPHIC APPARATUS K Filed May 28, 1957 3 Sheets-Sheet 1 Robert L.Guentner 8| Horrg E.Koerner June 23, 1959 R. L. GUENTNER ETALRADIOGRAPHIC APPARATUS Filed May 2a,- 1957 3 Sheets-Sheet 2 Figf.

Figd.

`Fig.6b.

3 Sheets-Sheet 3 June 23, 1959 R. L. GUENTNER ET AL RADIOGRAPHICAPPARATUS Filed May 28. 1957 United Safes Patent O 2,892,039 RAmoGRAPHrcyAPPA'RlrrUs application May 2s, 1957, serial No. 662,055 5 claims. (ci.25o-s6) 'East Pittsburgh, Pa., a corporation of The present inventionrelates to X-ray spot film radiographic devices and has more particularreference to apparatus for successive positioning ofv photographicplates to obtain a series oi X-ray photographs reasonablycontemporaneous with a visual iluoroscopic examination.

In iluoroscopic diagnosisV of human disorders, it is desirable to'photograph the fluoroscopically observed featuresV of the anatomy asquickly as possible after the visual observations. Abnormalities such asstomach ulcers' and the like are eetingly and uncertainly observable,thereby requiring a photographic apparatus capable ofrrapid andaccurately recording for yfuture reference and detailed study of theconditions observed. Severalapparatus having the foregoing capabilitiesare known to those skilled in the art and are generally referred to asspot lm devices. f *The known devices usually are comprised of thefolvowing elements or equivalent elements 'ha-vingsubstantially the samefunctions:

A flat substantially rectangular frame or `housing havg a pair of spacedopenings in the top surface thereof and havingy a carriage reciprocablyshiftable within the housing for transporting a ilm holder or cassettebetween van idle position at one end of the housing and an activeposition adjacent the second opening in the housing.` The secondfopening in the housing is adapted to contain a liuores'cent screen anda-lead glass superimposed on the uorescent screen to vscreen whileexcluding X-rays from Vthe face and eyes of the diagnostician. Therectangular frame of the spot iilm device is' ordinarily mounted above aconventional X-'ray table, on which table a patient may lie. The longdimension of the spot lm frame is ordinarily positioned Yat right anglesto the long dimension ofthe X-ray tablewith the first opening in theframe being toward the rear of the 'table and with the second opening inthe frame being disposed above the ltable surface in alignment with anallow visual observation of the the cassette carrying means must befirst a rs-t quadrant of the cassette with an X-ray beam. The carriagemust then be shiftable to the idle position during further visualobservation andmust be immediately ready, when in said idle position, tobe shifted to a second active position to align a second quadrant of afilm in the exact location previously occupied by the iirst quadrant.After exposure of the second quadrant to provide a second picture on thefilm, the cassette carriage is again shifted through the same cycleexcept that the cassette is laterally shifted to permit the laterallyadjacent third and fourth quadrants to be successively positioned inalignment with the X-ray beam. y

The type of apparatus thus far described is known to those skilled inthe art and may be conveniently grouped into two general classes,namely, gthose which are manually operated and those which are poweroperated as by means of an electric motor or an equivalent motor device.

In the manually operated spot film devices, it has been the practice forthe operator to reach into the lirst opening at the rear `of the spot lmdevice to manually push the film cassette fromV a lirst lateral positionto a second transversely shifted position. The necessity of manuallyshifting the cassette carrier laterally of the longitudinal carriageafter exposing the lirst two quadrants of the lm is an undesirabledistraction of the diagnostician from the uorescent image beingobserved. Further, it is an undesirable delay in the sequence ofsuccessive exposures and it requires that the diagnostician interruptthe manual palpation of the patients anatomy. Such interruption ofpalpation during the course of an examination often lm successively,shifted to align Y results in obscuring the particular anatomicalfeature Xray beam projected upwardly through the patient from an Xraytube disposed within the table. In order to obtana series of photographsin rapid succession, it is the practice to Vprovide an arrangement for'rapidly shifting a iilm cassette horizontally in the'spot iilm frame tosuccessively dilerent positions relative to the Xray beam, therebymaking it possible to obtain a sexies of pictures on a single sheet offilm. y

The cassette carrying means comprises a canriage'which is ordinarilymounted on rollers and travels on a pair of tracks or the like withinthe spot iilm device to carry the cassette from the cassette loading oridle positionto the various cassette active or photographing positions.The extent of4 movement of the carriage during successive 1cyclicalmovements is varied by means of adjustable stop elements disposed withinthe housing. Thus, `the devices :heretofore developed have provided forstopping thelongitudinal carriage `in at least two `active positionslongitudinally of the frame. Y y

In order to expose the four `quadrantsof-a which was to be photographed.Resumption of palpation does not assure the same view of fthe sameanatomical feature and a second opportunity to photograph a particularulcer or the like may not occur.

The improved spot iilm device of this invention may utilize any one of anumber of known arrangements for longitudinal shifting of thelongitudinally movable carriage means. The carriage means travels froman idle or loading position Within the iirst opening to successivelydifferent active or photographing positions underneath the fluorescentscreen. In addition, this'invention provides a novel arrangementincluding a transversely or laterally shiftable carrier supported on thecarriage The novel means. arrangement of this invention furtherincludesmeans for quickly and eiortlessly shifting the `cassette carriertransversely of the carriage means without requiring the diagnosticiauto reach into the first opening and without requiring significant delaybetween the second and third exposures of a single lm.

Thus the present invention provides means for individually andsuccessively positioning each of the four quadrants of a rectangular lmin alignment with the X-ray beam and such positioning is rapidlyaccomplished by a simple and eiiicient driving mechanism which requireslittle or no attention on the part of the diagnostician during thesequential positioning and exposure of the four iilm'quadrants. t

Accordingly, a principal object of this linvention is to provide a spotlm device utilizing automatic transverse .shifting of the cassettecarrier without delay or distraction of the diagnostician. t

It is another object of this invention to provide an improved transverseshift actuation means wherein the mechanism is rapid in operation and isless complex and hence less subject to faulty operation.

It is a further object to provide transverse shift actuation meanswherein free running movement of the cassette carrier to the secondtransverse position is obtained by the use of energy stored in themechanism prior to the'beginning of an examination, l f

It is. an additinnnl Object f this invention t9 provide a selectivelycontrollable cassette carrier shifting mechanism wherein the shiftingmechanism is easier to operate and is provided with simplified controlmeans.

It is a different object to provide a transverse shifting mechanismwhich includes yielding means for urging the cassette carrier toward thesecond lateral position and which further includes selectively operableposition control means including latching mechanism for normallyretaining the cassette carrier in a first lateral position withypotential energy for shifting the cassette carrier being stored in theyielding means.

These and other objects of our invention will be apparent from thefollowing description, taken in accordance with the accompanyingdrawing, throughout which like reference characters indicate like parts,which drawing forms a part of this application and in which:

Figure l is a plan view of a spot lm device in accordance with thepresent invention.

Fig. 2 is a plan View of the longitudinally shiftable subcarriageutilized in the apparatus of Fig. l.

Fig. 3 is a sectional view taken substantially along the Ilines III- IIIof Fig. 1 to illustrate the control mechaand latch mechanism of thetransversely shiftable carrier.

Fig. 4 is a plan view of the latch mechanism and control mechanism asshown in Fig. 3.

Fig. 5 is a view similar to Fig. 3, but depicting the control and latchmechanisms as oriented for center of the lm exposure positioning,

Fig. 6 is a plurality of diagrams illustrating successive positioning ofdifferent portions of a lm in the sequential operation of the apparatus,and

Fig. 7 is a sectional view taken substantially along the lines VIIVII ofFig. 2.

In Fig. l, there is shown a spot film device comprising generally ashallow rectangular casing or frame 10 including right and left sidewalls 12 and 14, a lateral front wall 16, a lateral rear wall 18 and atop cover panel 20 having portions cut away to provide a pair ofvsubstantially rectangular openings. The rst opening 21 is locatedtoward the rear of the spot film device and yis substantially largerthan the lm cassette to be used so that unexposed tilm cassettes may bereadily inserted into the apparatus through the iirst opening 21 and so:that the diagnostician or the assisting technician may ,convenientlyremove exposed cassettes therethrough. .'fhe second rectangular opening22 is disposed toward the front of the spot lm device. This secondopening 22 is 'covered by means of a conventional uorescent screen 23'and a lead glass 24 disposed thereon and secured to the top panel 20.

The under surface of the spot lm device frame is covered in aconventional manner by a plate of rigid material such as steel (notshown), a second plate of radiation opaque material, such as lead, andan outer radiation transparent panel of material such as aluminum orMicarta. The lead and steel plates have portions thereof cut away toprovide a rectangular opening in registration with the fluorescentscreen 23 so as to permit a beam of radiation from the X-ray tube to beprojected vertically to the iluorescent screen 23. The lead plate isnecessary in other areas of the spot lm device to shield a cassette inthe idle position from stray radiation and to shield the diagnosticianfrom radiation which otherwise might be projected upwardly past thesides of the lead-glass cover 24.

It is to be understood that the X-ray tube (not shown) is positioned inthe X-ray table in vertical alignment below the uorescent screen 23, andis provided with an adjustable shutter mechanism of a conventional typeso that the dimensions of the X-ray beam may be adjusted from time totime at the will of the operator. For example, during fluoroscopicexamination, the diagnostician may desire that the beam create an imageover substantially the entire area of. the fluorescent Screen 23-Likewise, ,the dimensions of the beam may be adjusted to provide asingle picture covering substantially the entire area of a singlecassette; or the beam may be adjusted to cover an area approximately thesize of one quadrant of a single cassette. This usual technique Vofutilizing a small area 'beam is illustrated by means of the circle 26shown in center of the uorescent screen 23 of Fig. l. The operation ofthe cassette shifting mechanism in conjunction with this small area beamto provide a plurality of sepa- .rate pictures on a single sheet of lmwill be discussed hereinafter.

Adjacent the front left-hand corner of the spot tilm device in Fig. l,there is shown a rotatable operating handle 28 which is journalled inthe, top cover 20 of the spot lm device and has a driving sprocket 30aixed to the lower end thereof. Adjacent the right side panel 12, of thespot lm device is a second sprocket 32 supported beneath the top cover20, and journalled on a mounting plate 34. The support shaft for thesecond "sprocket 32 also carries an elongated crank arm 36 af- !iixedthereto for rotation with the second sprocket 32,. The longitudinallymovable cassette carriage means com- ;rprising a carriage frame 38 ofrectangular form is mounted within the spot lm device and is providedwith rollers or wheels attached to the side members thereof to lrollagainst the` top panel 20, the bottom panel, andl the side panels 12 and14 of the spot iilm device. The sub .carriage 38 is adapted for movementlongitudinally of the spot lm device from registration with the firstlopening 21 to a plurality of longitudinally spaced posi,- tions inregistration with the fluorescent screen 23.`

As shown in Figs. l and 2, a transversely extending channel member 44 isattached to the front cross member 43 of the subcarriage frame 38. Aroller 37 mounted on the end of the crank arm 36 is disposed within thechannel member 44 so as to move the carriage 38 forward when the crankarm is rotated. A conventional interconnecting chain 31 extends from thecontrol handle sprocket 30 around a pair of idler sprockets 33 and 35 tothe second sprocket 32. Thus it is seen that byrotation of the controlhandle 28, the crank arm 36 may be rotated to move the subcarriage 38forward and backward in the spot film device between the tirst or idleposition and the diierent active positions.

Near the front ofthe spot iilm device is a fixed stop 46 for limitingforward travel of the subcarriage 38. Near the rear cross member 18 ofthe spot lm device is a rear stop block 48 atixed to limit rearwardtravel of the sub,4 carriage 38. The rear stop 48 is accuratelypositioned so that the subcarriage 38, when resting against the stop 48,is accurately registered with the rst opening 21 in the top panel.Adjacent the second sprocket 32 is a longitudinal position selectormechanism including a selector cam 50 in` the form of a parallelogrammounted for rotation about a vertical axis and journalled on themounting plate 34. The parallelogram selector earn 50 is provided with aratchet mechanism 52 and cooperates with a stop block 54 attached to theright slide of the subcarriage 38 so that each longitudinal extension ofthe subcarriage toward the f ront of the spot ilm device rotates theselector cam 5,0 through When the selector cam 50 is disposed in thefirst position, the subcarriage 38 is allowed to pass the selector cam50. and come to rest against the fixed stop 46. On the second excursionof the subcarriage 38 from the idle position toward the uorescent screen23, the selector cam 50 will have been rotated ,90 to the position asshown in Fig. 1 soA that the stop block 54 comes to rest against theselector cam 50, thereby arresting the subcarriage 38 in a partiallyextended second active position.

As'shown in Fig. 2, the subcarriage 38 has supported thereon atransversely shiftable cassette carrier comprising a structurally rigidrelatively ilat L-shaped frame/58 formedof a transversely extendingangle member 60 and ajlongitudinally extending angle member 62. Ayielding means, which may be a coil spring 64, is connected between onecorner ofthe transversely movable carrier 8 and a projection 66 on therear cross member 39 of the subcarriage 38. .Also connected between theprojection 66 and the transversely movable carrier 58 is anair dashpot68. A retaining flange 70 is atixed to the carrier 5 8 for retaining acassette 72 therein.V A spring-biased plunger pin 74 is mounted in asecond projection 76 on the rear cross member 39 of the subcarriage'andis operative to press against the rear edge of a cassette 72 to aid inretaining the cassette in the carrier 58. To this same end, adepressable casette retainer member 78 is affixed to the left end of themember 60. Midway of the left side member 41 of the subcarriage is afixed stop member 47 for limiting the transverse movement of a cassette72 when the cassette carrier 58 is transversely shifted from the firstposition as shown ,in Fig. `2 toward a second transversely shiftedposition.

iIrrorder to control transverse shifting of the carrier 58 ,under theinfluence of the tensioned coil spring 64, a

transverse position selector mechanism 82 is provided.

This mechanism includes an abutment member 84 in the Yform of acylindrical shaft extending -adjacent the front wall 43 of thelongitudinal carriage 38. The abutment `shaft 84 is journalled at itsends in appropriate bushings .86 and 88 aflixed to the longitudinalcarriage. The abutment shaft 84 includes intermediately of its endsthree spacedstop shoulders 91, 92 and 93 formed by cutting away portionsof the shaft 84. The three stop shoulders 91, 92 and 93 are spacedlongitudinally along the cylindrical shaft and are also spaced at 45intervals around the periphery of the shaft. A stop member in the formof .a flat leaf spring 94 is affixed to the front member 60 of thecarrier 58 with the end of the leaf spring 94 extending outwardlytherefrom so as to cooperatively engage `the stop shoulders 91, 92 and93 on the abutment shaft.

Attached to the end of the abutment shaft 84 is a detent mechanismincluding a square cam 96 and a cam follower 98 for selectively rotatingthe abutment shaft 84 to selectively dispose the shoulders 91, 92 or 93for cooperation vwith the stop member 94. -The detent mechanism is bestshown in Figs. 3 and 4 and includes the square cam 96 afiixed to the endof the abutment shaft 84 for rota- .tion therewith, a pin 99 atiixed tothe square cam 96 and extending outwardly therefrom, and the L-shapedvcam follower 9 8 which is pivotally connected to the subj carriage sidemember 45 and is spring-biased by means ofa spring member 100 tonormally maintain the square cam 96 in a first position as shown by thesolid lines in Fig. 3. An abutment shaft actuator arm 102 is pivotablyconnected near its center to the subcarriage side wall 45.

The actuator arm 102 is bifurcated at its left end to provide a slotwhich engages the eccentric pin 99. The

rightend of the actuator arm 102 is provided with a substantiallyV-shaped bifurcation which engages a control mechanism to be hereinafterdescribed,

On the inside of the right-hand side wall 12 of the spot Ifilm device ismounted a .transverse position control means l 1 4 including a levermember 106, a slider member 108 and a biasing spring 109. which connectsbetween frame member 12 and the slider member 108. As shown in Fig.v 3,the left end of the lever member 106 is disposed 'so as to engage theactuator arm 102 of the latch mechanism 82 when thesubcarriage 38 is inthe idle position. When the subcarriage 38 moves from the idle positiontowards the active positions, the actuator member 102 is Ic :arriedwiththe subcarriage. Thus, it is seen that the lever member 106 operativelyengages the actuator mem- '4ber 102 only when the subcarriage 38 is inthe idle or loading position. The lever member 106 is atiixed to the 1frame 12 near its center so as to be pivotable in a vvertical iplane.`The right endV of the lever member 106 carries a short pin 110 whichprojects perpendicular therefrom Sali@ estese an. elongated slantedspelling 1.1.1, in the .Slider 7 5 108. The slider member 108 is axed tothe inside of the frame 12 by means of a pairof rivets 114 and115 whichare rigidly affixed in the frame 12 and which pro'.- jects through apair of elongated horizontal openings 116 and 118 in the slider member108. Thus, it is seen that the slider member 108 is mounted on the innerwall of the frame 12 and is movable through a limited distance relativethereto. The spring'member 109 is attached to the slider member by anyconvenient means and is operative to rearwardly bias the slider member108. The slider member 108 includes a vertically extending portion 107which extends upwardly through an elongated slot 120 in the top panel 20of the spot lm device and s provided with a knob 122 at the upper endthereof for convenience in manual actuation.

On the bottom surface of the slider member 108, as viewed in Fig. 3, isa projection 124 disposed to lbe Vengaged by a connector member 126which is attached to the end of a pull wire 128. A detent device 130including a spring loaded plunger 132 mounted on the under side of thetop panel 20 and a notch 133 in the top surface of the slider member 108is operative in conjunction with the function of the shift knob 122,which function will be hereinafter described. It is to be understoodthat the shift knob 122 and its operatively associated detent mechanism130 are used only in conjunction with auxiliary positioning of theslider member 108. In the ordinary operation of the apparatus forsuccessive exposure of four quadrants of a film, the knob 122 is notused but the slider member 108 is actuated solely by means of the cable128. `The pull wire or cable 128 is connected at its left Ito anoperators push button mechanism 134 and extends from the push buttonmechanism to the slider member108 inside the right-hand portion of thespot film device. The spring biasing member 109 is operative to bias theslider member 108 toward the rear of the frame 12 and is sufficientlystrong to retract the slider member 108 and the cable 128 after theslider member 108 has been pulled forward by pressing down on theoperators control push button 136. A stop member is provided adjacentthe lower edge of the slider member 108 and is operative to engage theconnector member 126 so.as to limit the lforward travel of the connectormember .126 and the slider member 108. The stop members associated withthe slider member 108 may,l of course, be made adjustable if so desired.

In Fig. 3 the unlatching mechanism 104 is shown with the slider 108 inthe unactuated or rearmost position so that the slanted opening 111 inthe slider member operates to push the right end of the lever member 106down to thereby elevate the right end of the actuator aim 102. The leftend of the actuator arm 102 is accordingly shown in the depressed ornormal position with the square cam 96 being positioned with its topsurface substantially horizontal. It is to be understood that therotational position of the square cam 96 is controlled by the actuatorarm 102 but that the square cam 96 is also actuated by means of thespring biased cam follower 98.

As was explained above, the transverse position latch mechanism 82including the square cam 96, the cam follower 98 and the actuator arm102 are adjustably affixed to the subcarriage 38 and travel. therewithwhen subcarriage 38 is shifted from the idle position to its activepositions under the fluoroscopic screen 23. In

contrast, the unlatching mechanism 104 including lever member 106,slider member 108, and cable 128 are aixed to the frame 12 for limitedmovement only relative thereto. Thus, it is clear that lever member 106engages the actuator arm 102 only when the subcarriage 38 is in the idleposition and that push button 136 is not operative to actuate thelatching mechanism 82 after the subcarriage 38 has left the idleposition.

'Ihe operation of the transverse position control means fas shown `inFigs. 3, 4 and 5 is substantially as follows.

In order to successively expose the `four quadrants of a single lm, theoperator manually rotates control handle 28 in4 the counterclockwisedirection. Rotation of the second sprocket 32 will rotate the crank arm36 about its pivot, and subcarriage 38 will move forwardly from the idleposition to come to rest against the parallelogram cam 50. Thetransverse position control mechanism 104 will be in the position shownin the solid lines of Fig. 3 and the abutment shaft 84 will berotatively oriented so that stop member 94 is engaged with the firstshoulder 91. Thus, the cassette carrier 58 will be disposed in its firstlateral position relative to the subcarriage 38 and quadrant A of thecassette will be disposed in alignment with the X-ray beam for exposure.

After the X-ray tube is energized and the first exposure is completed,the operator turns the control handle 28 counterclockwise, therebyreturning subcarriage 38 to the idle position at which time the operatormay continue visual examination with the fluorescent screen 23. When itis desired to record a second image, the operator again rotates thecontrol handle 28 counterclockwise to again move the subcarriage 38forward. The parallelogram cam member 50 is now disposed to allow thesubcarriage 38 to pass, and the subcarriage moves all the way forwardand comes to rest against the front stop member 46. When the subcarriage38 is thus shifted to its furtherrnost extended position, quadrant B ofthe film is aligned with the circle 26 defined by the X-ray beam and thefilm is exposed as shown in Fig. 6B. After energizing the X- ray tube toexpose quadrant B the operator may again return the subcarriage 38 tothe idle or parked position.

Prior to a third excursion of the longitudinal subcarriage the operatordepresses the latch control push button 136 which is mounted axially inthe control handle 28, thereby tensioning cable 128 and shifting theslider member 108 forward to the position shown by the dotted lines inFig. 3. This action pivots lever member 106 and the actuator arm 102 torotate the abutment shaft 84 45 counterclockwise as shown in Fig. 3.Rotation of the abutment shaft 84 disengages stop member 94 from thefirst shoulder 91 of the abutment shaft, and cassette carrier 58 isallowed to travel toward the left as shown in Fig. l under the infiuenceof the coil spring 64. The cassette 72 is thus shifted transversely andis stopped by stop member 94 engaging the third shoulder 92 of abutmentshaft 84. After having depressed the control push button 136 as justdescribed the operator may immediately rotate the control handle 28counterclockwise to shift the subcarriage 38 forward. The subcarriage 38comes to rest against the parallelogram cam member S0, and the cassette72 is thus positioned as shown in Fig. 6C for exposure of quadrant C.Immediately after exposure of quadrant C the operator may return thesubcarriage 38 to the idle position in the same manner as previouslydescribed and may theneafter at any convenient time again move thesubcarriage forward to its forwardmost position for exposure of quadrantD. After exposure of quadrant D the diagnostician or the assistingtechnician may remove the exposed cassette 72 containing a series offour separate photographic images from the carrier by reaching into thefirst opening 21. The carrier 58 is at this time shifted to the left asseen in Fig. l. In order to load the apparatus for another fouron-oneseries, the technician uses an unexposed cassette to push the carrier 58transversely so as to extend the coil spring 64 and automatically latchthe carrier 58 in its first position with stop member 94 engaging firstshoulder 91 of the abutment shaft 84. The weight of the cassette and itsinertia as it is pushed into the first opening 21 under retaining lip 70aid in stretching the coil spring 64 so as to cock the transversepositioning mechanism 82 for a second series of four pictures. It i's tobe understood that the transversely shifted position of the cassettecarrier 58 brings the cassette 72 into engag'ement with stop member 47attached to side member 41 of the subcarriage. Thus, it is seen that thetransversely shifted position of the carrier 58 does not depend on stopmember 94 being held by the third shoulder 92 of the abutment shaft.From Fig. 3 it may Abe seen that the abutment shft 84 rotates back tothe solid line position as soon as the subcarriage 38 leaves the idleposition. This reorientation of the latching mechanism 82 does notaffect the transversely shifted position of the carrier 58 but merelyresets the latching mechanism 82 so that it willA automatically engagein the first transversely shifted position when an unexposed cassette isforceably inserted into the carrier.

The preceding operation of the apparatus has related to the so-calledfour-on-one technique or mode of operation in which the four quadrantsof a single film are individually exposed to the X-ray beam either inrapid succession or with any desired interval between successivepictures.

Fig. 6E illustrates an auxiliary mode of operation commonly referred toas the two-on-one technique. In this technique the film holder orcassette 72 is centered transversely of the spot lm device in a thirdtransversely shifted position determnied by the third shoulder 93 of theabutment shaft member 84. The front and rear halves of the film may thenbe successively exposed in transversely centered position to prvide twotransversely extending pictures on a single sheet of film. The sectionalarea of the X-ray beam is, of course, adjusted by means of theconventional X-ray shutters to expose only the limited rectangular areaas shown in Fig. 6E. The adjustment of the latch mechanism 82 to providetransverse centering of the cassette carrier 58 by means of the thirdshoulder member is shown in Fig. 5. As shown in Fig. 5 the carriercentering knob 122 is pulled forward manually until spring presseddetent plunger 132 engages the notch 133 in the upper surface of theslider member 108. The slider member 108 will therefore hold itsposition against the pull of tension spring 109 and will remain in thisposition until manually returned to the normal operating condition. Theaforesaid manual shifting of the slider member 108 locates it in aforwardmost position as shown in Fig. 5. The lever member 106 is pivotedthrough a greater angle than heretofore, and the actuator arm 102consequently moves the square cam 96 through an angle of approximatelyAs soon as the actuator arm 102 has moved the square cam 96 through anangle appreciably greater than 45, the cam follower 98 will operate tofurther rotate the square cam 96 to a full 90 rotated position. It maybe seen from Fig. 2 that this 90 rotation of the abutment shaft bringsthe intermediate shoulder 93 into position to engage the spring leafstop member 94. When the abutment shaft 84 rotates as just described,the stop member 94 will be automatically disengaged from the firstabutment shoulder 91, the cassette carrier 58 will automatically movetransversely under the influence of the coil spring 64, and will bestopped in center position by engagement of the stop member 94 with theintermediate abutment shoulder 93. The longitudinal subcarriage 38 maythen be successively shifted to the first and second longitudinallyspaced active positions to expose the front and rear halves of thecassette as shown in Figs. 6E and 6F. This two-on-one technique may berepeated any number of times by inserting unexposed cassettes 72 aftereach pair of pictures until such time as the diagnostician chooses toreturn to the normal or four-on-one technique. In order to return to thefour-on-one technique the operator simply pushes the one-on-one controlknob 122 toward the rear of the spot film device to disengage the detentplunger 132 from the notch 133 in the slider member 108. The slidermember 108 and hence the latch mechanism 82 will thereafter be under thecontrol of the push button actuated cable 128. It should be observedthat durthat it is ing the two-on-one technique the .abutment shaft 84remains at all times in the 90 rotated positionand is held in thatposition by the cam follower 98. 'Ihe left end of the lever member 106remains in 4the depressed position as shown in Fig. 5, and the right endof cam actuator 102 remains in the depressed position so that the twowill disengage when the subcarriage 38 moves from the idle position andwill smoothly reengage when the subcarriage returns tothe idle position.

If so desired, a third technique commonly referred to as the'one-on-onetechnique can be'utiliz'ed by providing means for positioning thesubcarriage 38 in longitudinally centered position relative to the X-raybeam. The knob 122 can then be actuated to center the cassette carrier58 both transversely and longitudinally so that a single picture of anydesired dimensions may be made on a single cassette 72.

It thus becomes obvious `to those skilled in the art that a spot lmdevice has been provided with which the diagnostician can make afluoroscopic `examination and simultaneously can take a variety of X-raypictures in a facile manner. By provision of the improved cassetteshifting and positioning mechanism an apparatus requiring a minimum ofeffort on the part of the diagnostician is achieved. In addition, theapparatus is easier to operate, is simplified in structure and henceless subject to faulty operation and does not require the diagnosticianto use his right hand for control of the carrier positioning mechanism.Freedom of the right hand is particularly advantageous in that itenables the diagnostician to continue palpation of the patients anatomyduring fluoroscopy and interstitial radiography.

While the present invention has form only,

been shown lin one it will be obvious to those skilled in the art not solimited but is susceptible of various changes and modications withoutdeparting from the spirit and scope thereof.

We claim as our invention:

l. In an X-ray spot film device including a frame, a subcarriage movablein a first direction between an idle position and at least one activeposition, a transversely shiftable cassette carrier supported on saidsubcarriage for movement relative thereto in a second direction betweena iirst position and a second position, and tensioning means supportedon said subcarriage for movement therewith and connected to saidcassette carrier to move said carrier from said lirst position towardsaid second position, the combination of a latch mechanism for holdingsaid cassette carrier in said iirst position including an elongatedabutment member aiiixed on said subcarriage for turning movement aboutits longitudinal axis, a stop member mounted on said cassette carrier,said abutment member being aligned substantially parallel to said seconddirection and having a plurality of shoulder members spaced therealongfor releasably engaging said stop member to define different transversepositions of said cassette carrier relative to said subcarriage, andmanually operated position control means for turning said elongatedabutment member to disengage said stop member from said shouldermembers.

2. In an X-ray spot lm device including a frame, a subcarriage meansmovable in a rst direction between an idle position and an activeposition, a carrier for supporting a photographic plate on saidsubcarriage means, said carrier being movable relative to saidsubcarriage means in a second direction substantially perpendicular tosaid rst direction between a irst position and a second position,tensioning means carried by said subcarriage means for movementtherewith and connected to said carrier to urge it toward said secondposition, the improvement comprising manually operated latch meansreleasably holding said carrier in lsaid rst position including anelongated abutment member having a plurality of shoulder members spacedtherealong and a stop member for engaging said shoulders, with saidabutment member be- `10 ing disposed with its long dimensionsubstantially parallel to said second direction and said stop memberbeing afxed for relative movement with respect to the length of saidabutment member, and manually operated trip means for actuating saidabutment member to disengage said stop member from said shouldermembers, said trip means including a first operators control meanspositioned on said frame adjacent said idle position solas to beconvenient for manual actuation and means to operatively connect saidoperators control means to said abutment member when said subcarriagemeans is in said idle position.

3. In an X-ray spot film device including a frame, a subcarriage movablelongitudinally of said frame between an idle position and an activeposition, a cassette carrier mounted on said subcarriage for movementthereon transversely of said frame between trst and second transverselimit positions and a transverse intermediate position, the combinationtherewith of a stop member carried by said cassette carrier, anelongated abutment member rotatable about an axis extendinglongitudinally therethrough and mounted on said subcarriage in extensiontransversely of said frame, said elongated abutment member having firstand second longitudinally spacedapart stop shoulders disalignedcircumferentially of said axis and extending radially thereof forcooperation with said stop member to define the rst transverse limitposition and transverse intermediate position, respectively, of saidcassette carrier, spring means biasing said cassette carrier in thedirection of its second transverse limit position, and manually operatedmeans for effecting turning movement of said elongated abutment memberselected degrees to free said stop member from said rst stop shoulder topermit travel of said cassette carrier to said second stop shoulder orthere past, according to the degree of such turning movement selected.

4. In an X-ray spot iilm device including a frame, a subcarriage movablelongitudinally of said frame between an idle position and an activeposition, a cassette carrier mounted on said subcarriage for movementthereon transversely of said frame between rst and second transverselimit positions and a transverse intermediate position, the combinationytherewith of a stop member carried by said cassette carrier, anelongated abutment member rotatable about an axis extendinglongitudinally therethrough and mounted on said subcarriage in extensionytransversely of said frame, said elongated abutment member having firstand second longitudinally spaced-apart stop shoulders disalignedoircumferentially of said axis and extending radially thereof forcooperation with said stop member to detine the iirst transverse limitposition and transverse intermediate position, respectively, of saidcassette carrier, spring means biasing said cassette carrier in thedirection of its second transverse position, and manually operated meansfor elfecting turning movement of said elongated abutment memberselected degrees to free said stop member from said iirst stop shoulderto permit travel of said cassette carrier to said second stop shoulderor therepast, according to the degree of such turning movement selected,said manually operated means including a irst operators member foreffecting a degree of turning movement of said elongated abutment membersuicient to free said stop member from said rst stop shoulder for travelof said cassette carrier from its rst to its second transverse limitposition, and a second operators member for eiecting a degree of turningmovement of said elongated abutment member suflicient to free said stopmember from said first stop shoulder for engagement with said secondstop shoulder to permit travel of said cassette carrier from said rsttransverse limit position to said transverse intermediate position. V

5. In an X-ray spot iilm device including a frame, a subcarriage movablelongitudinally of said frame between an idle position and an activeposition, a cassette cari Il 'riier mounted on said subcarriage formovement thereon transversely of said frame between said 'rst and secondtransverse limit positions and a transverse intermediate position, thecombination therewith of a leaf spring stop member carried by saidcassette carrier, an abutment shaft rotatable about its own axis andmounted on said subcarriage in extension transversely of said frame,said abutment shaft having cutaway portions forming first and Secondlongitudinally spaced-apart radially extending stop Shoulders disalignedperipherally of said shaft for cooperation with the projecting end ofsaid leaf spring stop member to define the aforesaid rst transverselimit and intermediate positions of said cassette carrier, respectively,spring means biasing said cassette carrier in the direction of itssecond transverse limit position, and man- I2 ually operated means foreffecting turning movement of said elongated abutment shaft selecteddegrees to free said stop member from said first stop shoulder to permitits travel with said cassette carrier to said second stop shoulder ortherepast according to the degree of such turning movement selected.

References Cited in the le of this patent UNITED STATES PATENTS

